The following U.S. patent and publication are believed to represent the current state of the art: U.S. Pat. No. 4,440,177 to Anderson et al, describes a respiratory analyzer system. Reference is also made to NIH publication on. 97-4051 entitled “Guidelines for the Diagnosis and Management of Asthma” pp 108-                109, 1991.        
The disclosures of all references mentioned above and throughout the present specification are hereby incorporated herein by reference.